Chthonius (C.) cavernarum Ellingsen, 1909

Gardini, Giulio, 2014, The species of the Chthonius heterodactylus group (Arachnida, Pseudoscorpiones, Chthoniidae) from the eastern Alps and the Carpathians, Zootaxa 3887 (2), pp. 101-137 : 103-107

Chthonius (C.) cavernarum Ellingsen, 1909

( Figs 1–11 , 90 )

Chthonius cavernarum Ellingsen 1909: 217 (in part); Hadži 1930: 128, figs 7a–f; Beier 1939b: 16, fig. 13.

Not Chthonius cavernarum: Ellingsen 1909: 217 (misidentification in part, see C. heterodactylus and C. raridentatus ); Beier 1928: 313 (misidentification, see C. raridentatus ); Beier 1931: 91 (misidentification, see C. raridentatus ); Beier 1932: 53 (misidentification, in part: see C. raridentatus ).

Type locality: Slovenia, Gorenjska regija, Škofja Loka, “Bischoflacker Grotte”, not identified but presumably either Migutovo brezno no. 5 (451 m a.s.l., 46°09′36.7″ N 14°17′ 51.7″E) or Marijino brezno no. 6 (429 m a.s.l., 46°09′45″ N 14°17′ 50″E).

Distribution. NE Italy, Romania, Slovenia.

Diagnosis (♂♀). An eyed, epi- or endogean Chthonius (Chthonius) from the eastern Italian Alps, Slovenia and southern Romania that differs from other species of the heterodactylus group in the following combination of characters: carapace usually without epistome, chaetotaxy 4:6:4:2:2 (18); chaetotaxy tergites I–IV: 4:4:4:4; genital opening of male flanked by aligned setae on each side; fixed chelal finger with 17–24 (♂) or 15–20 (♀) teeth with dental canals, usually with intercalary microdenticles, and with a distoparaxial spatulate seta; distal half of movable chelal finger with 8–15 (♂♀) sharp, triangular teeth that are higher than wide, erected or weakly inclined forwards; coupled sensilla pc of movable chelal finger between trichobothria st and sb; chela length 1.00–1.67 (♂) or 1.00–1.77 (♀); movable finger length 0.59–0.91 (♂) or 0.60–1.00 (♀).

Type material examined. ROMANIA— Prahova: 1 ♂ (paralectotype, present designation) “Carpathes / Sinaia Valachie / A. L. Montandon” “III. Chthonius cavernarum Ell. ” ( MSNG).

SLOVENIA— Gorenjska regija: 1 ♀ (lectotype, present designation), 9 ♂, 5 ♀, 2 T, 1 D (paralectotypes, present designation), “140 Chthonius / cavernarum Ell. n. sp. / Austria: Krain Sever” [= “Bischoflacker Grotte” (see Ellingsen 1909), not identified, but presumably either Migutovo brezno no. 5, 451 m a.s.l., 46°09′36.7″N 14°17′51.7″E or Marijino brezno no. 6, 429 m a.s.l., 46°09′45″N 14°17′50″E, both located near Škofja Loka] ( ZMUN). Osrednjeslovenska regija: 1 ♂, 1 ♀ (paralectotypes, present designation), “142 Chthonius / cavernarum , E. / Austria: Krain” [= “Zaorlihöhle” (see Ellingsen 1909), now Jamovka no. 107 (= Jama na Pokojišču, Gmanjska jama, Jama na Zavrhu), 710 m a.s.l., 45°54′12″N 14°20′28″E] ( ZMUN).

Other material examined. ITALY — Friuli: Udine Prov.— 1 ♂, Nimis, Grotta di Monteprato 59 Fr/UD, 525 m a.s.l., 26.III.1983, F. Gasparo leg. (together with 1 ♂ of C. raridentatus ).

SLOVENIA— Notranjsko–Kraška regija: 2 ♂, “10 [illegible] Koschir Luka [Luka Košir leg.] Doline b[ei] Adelsberg. Verh[oeff]” ( ZMHB, KatNr. 31638); 2 ♂, Postojna, Rakov Škocjan, 520 m a.s.l., 5.X.1991, F. Gasparo leg. (together with 1 ♂, 2 ♀ of C. raridentatus ); 1 ♂, 4 ♀, Postojna, Lož, 600 m a.s.l., 14.X.1990, F. Gasparo leg. (together with 1 ♂, 1 ♀ of C. raridentatus ); 3 ♂, 6 ♀, Snežnik, Sviščaki, 1250 m a.s.l., 25.VIII.1991, F. Gasparo leg. (together with 10 ♂, 4 ♀ of C. raridentatus ). Osrednjeslovenska regija: 1 ♂, between Grosuplje and Turjak, 450 m a.s.l., 10.IX.1991, F. Gasparo leg. Spodnjeposavska regija: 1 T, Brežice, 28.VIII.1987, G. Gardini & R. Rizzerio leg. (together with 2 ♀ of C. raridentatus ).

Description of adults (♂♀). Carapace, tergites, chelicerae and pedipalps brown or pale brown (lecto- and paralectotypes decoloured); hispid granulation on lateral surfaces of carapace, on cheliceral palm and on distal surface of pedipalpal hand. Carapace 0.9–1.1 times longer than broad, weakly constricted posteriorly; anterior margin usually without epistome ( Figs 1–2 ) (rarely weakly developed: Fig. 3 ), with sharp denticles between median macrosetae; ocular area as in Figs 4–5 , anterior eyes with weakly convex lens (diameter 0.040–0.050 mm), posterior eyes reduced to spots, tapeta usually evident in recently preserved specimens; distance from anterior eyes to anterior margin of carapace 0.030–0.040 mm; chaetotaxy 4:6:4:2:2 (18), respective lengths of anteromedian and anterolateral macrosetae 0.14–0.16 and 0.07–0.08 mm, length of median macrosetae of ocular row 0.17–0.20, length of posterior macrosetae 0.17. Chaetotaxy of tergites I–X 4:4:4:4:6:6:6:6:6:4. Chaetotaxy of sternites II–X 10:(3)9–10(3):(2)7–8(2):8:6:6:6:6:7; sternite II rarely with 9 setae, sternite III rarely with 8 setae; genital opening of males flanked by 8–9 (rarely 6) setae on each side. Chelicera ( Figs 6–8 ) 2.2–2.4 (♂♀) times as long as broad, palm with 6 setae and 1 (rarely 2) microseta laterally; fixed finger with 10–12 teeth (second tooth from distal end larger and sharp) and a few proximal microtubercles; movable finger with an isolated subapical tooth (di), 8–10 teeth proximally reduced in size and 4–5 proximal tubercles; gl ratio 0.50–0.62; spinneret weakly prominent in males ( Fig. 6 ), rarely absent ( Fig. 8 ), prominent and apically rounded in females ( Fig. 7 ); rallum with 11 blades; serrulae interior and exterior respectively with 15 and 17 blades. Coxal setae: pedipalp 5 (including 2 on manducatory process), I 3 + 3 marginal microsetae, II 4, III 5, IV 6; coxa II with 9–12 (rarely 15) coxal spines, coxa III with 4–5 (rarely 8) coxal spines; intercoxal tubercle bisetose. Pedipalp: femur 6.2–8.0 (♂) or 6.2–7.3 (♀) times as long as broad; chela ( Figs 9–11 ) 5.5–6.9 (♂) or 4.5–5.9 (♀) times as long as deep; hand of chela 1.9–2.3 (♂) or 1.7–1.9 (♀) times as long as deep; fixed finger with marked sigmoid curvature in lateral view (less marked in ♂ from Grotta di Monteprato 59 Fr/UD), with 17–24 (♂) or 15–20 (♀) teeth with dental canals, usually with 1– 3 intercalary microdenticles in most interdental spaces [1 ♀ (out of 3 ♂, 6 ♀) from Snežnik: Sviščaki without intercalary microdenticles]; distal tooth reduced, usually halfway between et and it in males, but nearer to it in females; 14–20 (♂) or 12–15 (♀) large, sharp, weakly reclined teeth increasing in size as far as halfway along the finger, then decreasing in size towards the finger base; 1–4 (♂) or 3–5 (♀) small proximal teeth with rounded tips and dental canals; base of fixed finger with 0–4 microtubercles; fixed finger at level of it/est with 3 (rarely 2) teeth occupying 0.1 mm (distance between successive apices 0.030–0.050 mm); tip of fixed finger with sensilla af1 ‾ 2, distal paraxial seta spatulate, enlarged in the middle and acuminate apically; movable finger strongly curved in lateral view and always shorter than fixed finger, with 22–29 (♂♀) teeth, all with dental canal; distal half of movable finger with 1 (rarely 2) low, broad distal tooth followed by 8–15 (♂♀) triangular, sharp, higher than wide teeth that are erected or weakly inclined forward; proximal half of movable finger with 9–15 (♂♀) low, broad, reclined teeth increasingly reduced towards finger base, reaching back to halfway between sb and b, followed by 3–8 vestigial teeth usually discernible only by the presence of dental canals; coupled sensilla pc usually halfway between st and sb; tip of movable finger with sensilla am1 ‾ 2; trichobothria as in Figs 9–11 , eb -esb -ist placed in a straight line, or with ist distad of the line eb/esb; ratio of movable finger/hand of chela 1.6–1.8 (♂) or 1.6–1.7 (♀); ratio of pedipalpal femur/movable finger 1.1–1.2 (♂♀); ratio of pedipalpal femur/carapace 1.3–1.9 (♂♀).

Measurements (in mm). Body length 1.7–2.2 (♂♀). Carapace 0.47–0.62 × 0.46–0.56 (0.42–0.52 anteriorly) (♂) or 0.43–0.64 × 0.47–0.62 (0.44–0.59 anteriorly) (♀). Chelicera 0.43–0.59 × 0.19–0.25 (♂) or 0.44–0.64 × 0.19–0.27 (♀); movable finger length 0.24–0.30 (♂) or 0.24–0.34 (♀). Pedipalp: femur 0.67–1.13 × 0.10–0.14 (♂) or 0.65–1.17 × 0.10–0.16 (♀); chela 1.00–1.67 × 0.18–0.24 (♂) or 0.99–1.77 × 0.185–0.30 (♀); hand length 0.35–0.55 (♂), 0.35–0.59 (♀); fixed finger length (from tip to eb) 0.65–1.05 (♂), 0.65–1.14 (♀); movable finger length 0.59–0.91 (♂), 0.60–1.00 (♀).

Description of tritonymph. Integument pale, hispid granulation less marked than in adults. Carapace 1.00–1.05 times longer than broad, anterior margin without epistome, denticles as in adults; anterior eyes with weakly convex lens, posterior eyes reduced to eye-spots; chaetotaxy 4:6:4:2:2 (18), length of anteromedian and anterolateral macrosetae respectively 0.11–0.12 and 0.05 mm, length of median macrosetae of ocular row 0.15 mm, length of posterior macrosetae 0.10 mm. Chaetotaxy of tergites as in adults. Chaetotaxy of sternites II–X 5:(2)8(2):(1)6(1):7:6:6:6:6:7. Chelicera 2.2–2.3 times as long as broad, palm with 5 setae and 1 microseta laterally; fixed finger with 11 teeth, the distal two larger, the following proximally reduced in size; movable finger with an isolated subapical tooth (di) and 8–9 teeth; gl ratio 0.52; spinneret prominent and apically rounded, as in females; rallum with 9 blades; serrula exterior with 13 blades. Coxal setae: pedipalp 5 (including 2 on manducatory process), I 3 + 2 marginal microsetae, II 4, III 5, IV 5; coxa II with 13–15 coxal spines, coxa III with 5–6 coxal spines; intercoxal tubercle bisetose. Pedipalp: femur 6.4 times as long as broad; chela 5.9 times as long as deep; hand 2.15 times as long as deep; fixed finger with 18–22 teeth with dental canals, with 1– 2 intercalary microdenticles in most interdental spaces; first distal tooth reduced, situated at level of et; 17–21 large, sharp, weakly reclined teeth increasing in size as far as halfway along the finger, then reduced in size towards the finger base; 2–3 small proximal teeth with rounded tips and with dental canals; base of fixed finger with 2–3 microtubercles; fixed finger at level of it/est with 3 teeth occupying 0.1 mm (distance between successive apices 0.040–0.043 mm); distal paraxial seta as in adults; movable finger shorter than fixed finger; movable finger with 26 teeth, all with dental canal; distal half of movable finger with 1 low, broad distal tooth followed by 10 triangular, sharp, higher than wide teeth, erect or weakly inclined forward; proximal half of movable finger with 15 low, broad, reclined teeth increasingly reduced towards finger base, reaching back almost to b; coupled sensilla pc halfway between st and b; trichobothrium ist distad of line eb/esb; ratio of movable finger/hand 1.6; ratio of femur/ movable finger 1.15; ratio of femur/carapace 1.5–1.6.

Measurements (in mm). Body length 1.5–1.7. Carapace 0.44–0.49 × 0.43–0.47 (0.41–0.43 anteriorly). Chelicera 0.41–0.43 × 0.18–0.19, movable finger length 0.20–0.22. Pedipalp: femur 0.71–0.74 × 0.11–0.12; chela 1.05–1.10 × 0.17–0.18; hand length 0.39–0.40; fixed finger length (from tip to eb) 0.68–0.70; movable finger length 0.62–0.64.

Remarks. Ellingsen (1909) described Chthonius cavernarum from 26 syntypes from two caves in Carniola (now in Slovenia)—“Bischoflacker Grotte” (20 specimens) and “Zaorlihöhle” (2 specimens)—and from Sinaia, Romania (4 specimens). Harvey (1991, 2013) listed only Sinaia as the type locality, but this was due to a simple oversight (M.S. Harvey in litt.). Because the syntypes are now attributed to three different species ( C. cavernarum , C. heterodactylus and C. raridentatus : see below under C. heterodactylus and C. raridentatus ), a lectotype is designated here to ensure nomenclatural stability. Accordingly, under the Article 74.1.3 of the Code ( International Commission on Zoological Nomenclature 1999), all the other syntypes become paralectotypes of C. cavernarum , including those that were misidentified by Ellingsen (1909). Four paralectotypes not listed above [2 ♀ of C. heterodactylus ( Romania, Sinaia) and 2 ♀ of C. raridentatus ( Slovenia, Bischoflacker Grotte)] are mentioned under “Material examined” of the respective species. The female lectotype of C. cavernarum (lacking the right chela) is probably the specimen used by Ellingsen (1909) in description of the species. The measurements given by Ellingsen (1909) and those obtained here for the female lectotype (in brackets) are: carapace 0.64 (0.64) x 0.61 (0.59) anteriorly, chelicera length 0.64 (0.64), pedipalpal femur 1.37 (1.17) x 0.16 (0.16), hand 0.60 (0.59) x 0.29 (0.30), fixed finger length 1.14 (1.14), movable finger length 0.94 (1.00) mm. Ellingsen’s original description highlights one of the most important diagnostic characters, namely the dentition of movable chelal finger: “the inner margin in the distal part provided with small, conical teeth, smaller than those of the fixed finger, also with great intervals, but with no traces of smaller teeth between them; the teeth are growing lower backwards” ( Ellingsen 1909). Beier (1928) considered it probable that C. cavernarum was synonymous with C. heterodactylus and noted the difficulties in detecting intercalary denticles on the fixed chelal finger (see Remarks under C. raridentatus for misidentifications between C. cavernarum and C. ellingseni by Beier 1928, 1931, 1932). Hadži (1930) rejected the synonymy suggested by Beier (1928) and correctly identified name and location of the Zaorlihöhle, one of the type localities of C. cavernarum . Hadži (1930) redescribed the species using a male from the cave “Žabja usta” (now Migutovo brezno no. 5, possibly the type locality: see ‘ Type localities’ above) near Škofja Loka, Slovenia. Beier (1932) overlooked Hadži’s (1930) contribution and redescribed C. cavernarum , combining data from Ellingsen’s original description (body length and measurements of pedipalpal femur) with data from a specimen—probably a male, of unknown origin—of C. ellingseni (measurements of pedipalpal hand and fixed and movable fingers, with a figure of the pedipalpal chela). C. cavernarum was at last redescribed by Beier (1939b) [repeated in Beier (1963)] on a male from the cave Breznohöhle ober Bischoflak (now Migutovo brezno no. 5) near Škofja Loka, Slovenia. The measurements given by Hadži (1930) and Beier (1939b) agree with those in the above description. Ćurčić (1974) erroneously gave “Postojnska Jama” as the type locality of C. cavernarum , probably following a previous citation of the species from “Krain, Grotte bei Adelsberg” by Ellingsen (1910) (see above in ‘Other material examined’).

Chthonius cavernarum is a troglophilic species known from the eastern Venetian pre-Alps to Slovenia and southern Romania ( Fig. 90 ). Among the species of Chthonius of the C. heterodactylus group, C. cavernarum seems to be related to the sympatric (rarely syntopic) C. raridentatus . Differences between C. cavernarum and C. raridentatus are given in the above key. The presence of C. cavernarum in Italy ( Gardini 2000) is here confirmed. Records of Chthonius subterraneus Beier, 1931 from Hungary ( Szent-Ivány 1941) and Slovakia (Krumpál & Krumpálová 2003, Christophoryová et al. 2011b, 2012) are doubtful and remain to be verified since C. subterraneus (type locality: Montenegro, Herceg Novi) displays a dentition of the movable chelal finger identical to that of C. cavernarum .

Figures

FIGURE 90. Distribution map for Chthonius (C.) cavernarum Ellingsen, 1909 (▲), C. (C.) heterodactylus Tömösváry, 1882 (Δ), C. (C.) hungaricus Mahnert, 1981 (■), C. (C.) lessiniensis Schawaller, 1982 (□), C. (C.) pusillus Beier, 1947 (●), C. (C.) raridentatus Hadži, 1930 (○).

FIGURES 1 – 11. Chthonius (C.) cavernarum Ellingsen, 1909. 1 – 3, Anterior margin of carapace of ♂ (Slovenia) (1), ♀ (Slovenia) (2) and ♂ (Italy) (3). 4 – 5, Anterolateral portion of carapace of ♂ (Slovenia) (4) and ♂ (Italy) (5). 6 – 8, Right chelicera of ♂ (Slovenia) (6), ♀ (Slovenia) (7) and ♂ (Italy) (8). 9 – 11, Right chela, lateral view, of ♂ (Slovenia) (9), ♀ (Slovenia) (10) and ♂ (Italy) (11). Figures 1, 2, 4, 6 – 7, 9 – 10: adults from Slovenia, Sviščaki; 3, 5, 8, 11: male from Italy, Grotta di Monteprato.